Abstract

Boundary scattering phonon mean free path (MFP) is an important parameter for thermal conductivity calculation of nanocomposites. In this work, a simple approximate model is proposed to predict boundary/interface scattering MFP and thermal conductivity of nanowireheterostructures (NWHSs) based on Casimir formalism. Calculated thermal conductivities of Si tubular nanowires and Si/Ge NWHSs agree well with the numerical and analytical solutions of Boltzmann transport equation. It is demonstrated that core/shell layer thickness plays a significant role on tuning NWHS thermal conductivity. The results indicate the approximate model of thermal conductivity can be used for quickly evaluating the thermal behavior of nanocomposites.